The present invention generally relates to seatbelt systems for automotive vehicles and, more particularly, to seatbelt usage indication systems for automotive vehicles.
The automotive industry has experienced significant growth with onboard safety information systems, also referred to as cabin communication systems. These systems help the vehicle operator better assess the status of the various vehicle conditions. Some of the vehicle conditions include inside temperature, door ajar, and seatbelt buckling. When a condition changes, the system alerts the operator with an audible, and or, a visual alarm transmitted from the onboard safety information systems. The onboard safety information system includes smaller systems that monitor specific conditions; such as identifying, among other things, the location of buckled and unbuckled seatbelts when the vehicle is in operation. The seatbelt indication system is one such system.
The seatbelt indication system can relay the information to the onboard safety information system or send the information directly on to the indication system to alert the operator. With the seatbelt indication system, the operator receives an alert identifying that seatbelts are, or are not, in use. The seatbelt indication system includes a sensor that gathers the seatbelt status from a sensor wired into the vehicle's cable harness and mounted on each seatbelt buckle assembly.
The cable harness is used to connect the seatbelt sensor to the seatbelt indication system. The cable harness provides power for the sensor. The cable harness also provides a continuous communication connection to send the seatbelt status to any other subsystem that might need the information.
For each seatbelt sensor connection, the associated cost to supply power and a communication link is proportional to the number of connections made. Furthermore, the routing of wires to transfer power or data is very difficult in a customer friendly way when the connection is to a foldable or removable seat. Also, each seatbelt sensor added increases the input ports needed to connect to the systems input circuitry in the seatbelt indication system.
A cable harness may prove to be unreliable where the seat is foldable or removable due to user error in the disengagement and engagement of a cable connection. The cable harness is more prone to wear or damage when routed to foldable and or removable seats. Also, the system may prove to be inoperable where the user might simply forget to reconnect a cable after disengaging it. Other means of making electrical contact connection with the sensor for a removable seat could be employed at or near the place where the seat connects to the floor, but these means would also be prone to contamination and abuse. It would be advantageous to provide seatbelt sensor that is not wired into a cable harness, but could still communicate seatbelt status to the seatbelt indication system.
In another configuration for removable seats, as disclosed in U.S. Pat. No. 6,362,734, the onboard safety information system gathers the seatbelt status from a non-contact data link. The non-contact data link consists of a closely adjacent non-powered transceiver/transponder connection. This non-powered wireless connection is comprised of a transponder and transceiver. The transponder is coupled to the removable seat and is electrically connected with the seatbelt sensors. The transceiver is attached to the automotive vehicle and electrically connected with the seatbelt indication system or other similar systems, as mentioned above. The transceiver is located in the vehicle so that it will be closely adjacent to the transponder when the removable seat is placed back into the automotive vehicle after removal. The closely coupled position between the transceiver and transducer must be maintained in order for the transducer to receive the radiated energy from the transceiver sufficient to power it. If the transceiver and transponder are not properly located adjacent to each other, then the non-powered transponder will not receive enough radiated energy necessary to send a signal back to the transceiver.
Also, each non-contact data link requires a transceiver/transponder set. And each transceiver requires a connection to the seatbelt indication system that increases the cost and system complexity if a transceiver/transponder is used at every seating location in the automotive vehicle.
In view of the above, it would be advantageous to have a self-powered wireless switch assembly that transmits the unbuckled or buckled status of the seatbelt not being dependent upon a closely coupled wireless or hardwired connection. It would also be beneficial to have the identity of the self-powered wireless switch assembly identifiable at the source. The final advantage would be to have a system that requires only one receiver to receive the status of one or more self-powered wireless switch assemblies onboard an automotive vehicle.